Sunsetter

**[[Home]] * [[Engines]] * Sunsetter**
|| [[image:Sunset_with_coconut_palm_tree_Fiji.jpg link="https://commons.wikimedia.org/wiki/File:Sunset_with_coconut_palm_tree,_Fiji.jpg"]] ||~ || **Sunsetter**,
an [[Open Source Engines|open source chess engine]] under the [[Free Software Foundation#GPL|GNU General Public License v2.0]] <ref>[[https://github.com/georgvonzimmermann/Sunsetter/blob/master/COPYING|Sunsetter/COPYING at master · georgvonzimmermann/Sunsetter · GitHub]]</ref> that plays [[Bughouse]] and [[Crazyhouse]] - a separate version also orthodox chess. Sunsetter is written by [[Georg von Zimmermann]] in [[Cpp|C++]], recent versions co-authored by [[Ben Dean-Kawamura]] <ref>[[https://github.com/georgvonzimmermann/Sunsetter/blob/master/README.txt|Sunsetter/README.txt at master · georgvonzimmermann/Sunsetter · GitHub]]</ref>, available at [[https://en.wikipedia.org/wiki/GitHub|GitHub]], compliant to the [[Chess Engine Communication Protocol]] <ref>[[https://github.com/georgvonzimmermann/Sunsetter/blob/master/interface.cpp|Sunsetter/interface.cpp at master · georgvonzimmermann/Sunsetter · GitHub]]</ref>. ||
|| Sunset  <ref>[[https://en.wikipedia.org/wiki/Sunset|Sunset]] from [[https://en.wikipedia.org/wiki/Fiji|Fiji]] over [[https://en.wikipedia.org/wiki/Pacific_Ocean|Pacific ocean]] with [[https://en.wikipedia.org/wiki/Coconut|coconut palm tree]], [[https://commons.wikimedia.org/wiki/File:Sunset_with_coconut_palm_tree,_Fiji.jpg|image]] by Andrew Mandemaker, April 17, 2006, [[https://creativecommons.org/licenses/by-sa/2.5/deed.en|CC BY-SA 2.5]], [[https://en.wikipedia.org/wiki/Wikimedia_Commons|Wikimedia Commons]]</ref> ||~ ||^ ||
[[toc]]
=Description=
<ref>based on [[https://github.com/georgvonzimmermann/Sunsetter|GitHub - georgvonzimmermann/Sunsetter: A crazyhouse chess playing program]]</ref>
==[[Move Generation]]==
Sunsetter is a [[Bitboards|bitboard]] engine which uses [[Rotated Bitboards|rotated bitboards]] to calculate [[Sliding Piece Attacks|sliding piece attacks]] <ref>[[https://github.com/georgvonzimmermann/Sunsetter/blob/master/bitboard.cpp|Sunsetter/bitboard.cpp at master · georgvonzimmermann/Sunsetter · GitHub]]</ref>. The [[Board Representation|board structure]] further keeps an [[8x8 Board|8x8 board]], and Crazyhouse specific, a bitboard of promoted pawns, and [[Piece-Lists|piece-lists]] of each player's reserve (in hand), also keeping some [[Incremental Updates|incremental updated]] [[Attack and Defend Maps|attack tables]]. [[Pseudo-Legal Move|Pseudo-legal moves]] are generated in four [[Move Generation#Staged|stages]].

==[[Search]]==
Sunsetter performs [[NegaScout]] with [[Transposition Table|transposition table]] within its [[Iterative Deepening|iterative deepening]] framework using a [[Null Window|zero]] [[Aspiration Windows|aspiration window]] to decide whether the forced re-search of the first move half-opens the [[Window|window]] in plus or minus infinity direction <ref>[[https://github.com/georgvonzimmermann/Sunsetter/blob/master/search.cpp|Sunsetter/search.cpp at master · georgvonzimmermann/Sunsetter · GitHub]]</ref>. [[Null Move Pruning|Null move pruning]], [[Futility Pruning#Extendedfutilitypruning|extended futility pruning]], [[Razoring|razoring]] and [[Extensions#FractionalExtensions|fractional extensions]] are used to shape the [[Search Tree|tree]], which has considerable larger [[Branching Factor|branching factor]] in Crazyhouse. Sunsetter features [[Book Learning|book learning]] based on the final result, where [[Ronald de Man#ScoringRootMoves|root moves receive a bonus]] if persistent from advantageous positions in previously won games.

==[[Evaluation]]==
Sunsetter's evaluation in [[Centipawns|centipawn]] resolution considers [[Material|material]], material in hand, [[Square Control|board control]], [[Development|development]], and [[King Safety|king safety]] <ref>[[https://github.com/georgvonzimmermann/Sunsetter/blob/master/evaluate.cpp|Sunsetter/evaluate.cpp at master · georgvonzimmermann/Sunsetter · GitHub]]</ref>.

=Forum Posts=
==2000 ...==
* [[http://www.stmintz.com/ccc/index.php?id=173342|Sunsetter(C) source released]] by [[Georg von Zimmermann]], [[CCC]], June 04, 2001
* [[http://www.stmintz.com/ccc/index.php?id=264297|Very interesting crazyhouse position-to Georg Zimmerman (sunsetter test)]] by Lieven Clarisse, [[CCC]], November 11, 2002
* [[http://www.stmintz.com/ccc/index.php?id=333517|Sunsetter C10 Anomaly]] by [[Matthias Gemuh]], [[CCC]], December 04, 2003
==2010 ...==
* [[http://www.open-aurec.com/wbforum/viewtopic.php?f=15&t=52922|Reborn of sunsetter?]] by velocidrom, [[Computer Chess Forums|Winboard Forum]], August 31, 2013
* [[http://talkchess.com/forum/viewtopic.php?t=50395|Sunsetter (crazyhouse engine) issue with ponder on, linux]] by Robert Tournevisse, [[CCC]], December 09, 2013
* [[http://talkchess.com/forum/viewtopic.php?t=64006|Sunsetter 9 under Arena GUI]] by Arnaud lohéac, [[CCC]],  May 17, 2017

=External Links= 
* [[http://sunsetter.sourceforge.net/|Sunsetter]] from [[https://en.wikipedia.org/wiki/SourceForge|SourceForge]]
* [[https://sourceforge.net/projects/sunsetter/files/|Sunsetter - at SourceForge.net]]
* [[https://github.com/georgvonzimmermann/Sunsetter|GitHub - georgvonzimmermann/Sunsetter: A crazyhouse chess playing program]]
* [[http://kirr.homeunix.org/chess/engines/Jim%20Ablett/SUNSETTER/|Sunsetter]] compiled by [[Jim Ablett]], hosted by [[Kirill Kryukov]]
* [[http://www.computerchess.org.uk/ccrl/404/cgi/engine_details.cgi?print=Details&eng=Sunsetter%2010.3%2064-bit#Sunsetter_10_3_64-bit|Sunsetter 10.3 64-bit]] in [[CCRL|CCRL 40/4]]

=References= 
<references />
=What links here?= 
[[include page="Sunsetter" component="backlinks" limit="30"]]
**[[Engines|Up one level]]**